Ciete d exploitation des cables electbiqijes systems beethoud



(No Model.)

ELECTRIC GABLE. No. 370,528. Patented Sept. 27, 1887.

"A! p was 4 5, 31

UNITED STATES PATENT OFFICE.

FRANCOIS BOREL, OF OOIt'lAILLOD, SWITZERLAND, ASSIGNOR TO THE SO- CIETEDEXPLOITATION DES CABLES ELEOTRIQUES SYSTEME BERTHOUD,

BOREL & CIE.

ELECTRIC CABLE.

SPECIFICATION forming part of Letters Patent No. 370.528, datedSeptember 27, 1887.

Application filed January 3, 1887. Serial No. 123,322. (No model.)

To all whom it may concern.-

Be it known that I, FRANQOIS BOREL, engineer, of Oortaillod,Switzerland, have in I vented a new and useful Improvement in ElectricCables, of which the following is a specification.

My invention relates to an electric cable constructed, as hereinafterdescribed, so as to prevent induced currents in other cables and toeconomize the materials made use of.

My invention is based upon the following principles: First,if anelectric currentthrough two concentric conductors passes in onedirection in the central conductor and in the opposite direction in theconcentric conductor no induced current is set up in the neighboringconductors; second, to economize insulating material the conductorsshould be parallel, otherwise the current is liable to pass where theconductors are nearest to each other.

In the accompanying drawings, Figure 1 shows a section of my improvedcable. Fig. 2 shows a modification of the same.

The central conductor, A, Fig. 1, containing one or more wires, issurrounded by ametallic tube,'13, or by helicalwound metallic ribbons;or these may be dispensed with, as seen in Fig. 2. The insulatingmaterial at O, surrounding the conductor, is of sufficient thickness toprevent the current passing from the conductor A to the tube D. Thetubular conductor D is preferably of helical-wound metallic wire, E.

ribbons surrounded by metallic F is a second coat of non'conductive material.

The exterior protecting-coat of the cable is formed of the two leadentubes G and I, between which is inserted a coating of hydrofugematerial, H, (rosin, paratiine, &c.)

The purpose of the tube B is to avoid accidents which might be producedby one of the wires of the conductor or a metallic splinter coming nearthe tube D and lessening the distance through the insulating material.

To obtain regularity in manufacturing the before-described cables, Iform the metallic coats B, D, G, and I by a machine similar to alead-pipe press, into which is introduced the insulating material, C andF, and the hydrofugematerial, H, in fusible state, as the cable ismanufactured.

I claim as my invention- The electric cable composed of the centralconductor, A, the insulating material, 0, surrounding the samc, theconcentric conductor D outside the insulating material, C, and parallelwith the conductor A, and the insulating envelope F and protecting-tubesG I, having hydrofuge material between them and being parallel to andconcentric with the conductor A, substantially as set forth.

Signed by me this 6th day of December, A. D. 1886;

FRANCOIS BOREL.

Witnesses:

EDOUARD DRAY, J. A. VVAREL.

